The northernmost distribution of Anhinga anhinga leucogaster is in the United States from North Carolina to Texas. It has however been spotted as far north as Wisconsin. Its range also includes Mexico, Central America, Panama, and Cuba. The individuals found in the more northern areas of the U.S. migrate there in March and April and stay until October, then return to Mexico and more southern parts of the Anhinga anhinga anhingais found in South America from Colombia to Ecuador, east of the Andes to Argentina, and in Trinidad and Tobago. The range is limited by cool temperatures and low amounts of sunshine.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
- Hennemann, W. 1985. Energetics behavior and the zoogeography of *Anhinga anhinga* and double-crested cormorants *Phalacrocorax auritus*. Ornis Scand., 16(4): 319-323.
- Isenring, R. 1997. By the Wayside. Passenger Pigeon, 59(4): 347-358.
- del Hoyo, J., A. Elliot, J. Sargatal. 1992. Handbook of the Birds of the World. Vol. 1, Ostrich to Ducks.. Barcelona: Lynx Edicions.
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDING: central and eastern Texas, southeastern Oklahoma, southern and eastern Arkansas, southern Missouri (formerly), western Tennessee, southern Illinois (formerly), north-central Mississippi, southern Alabama, southern Georgia, and coastal North Carolina south to southern Florida, Cuba, and Isle of Pines, and from Sinaloa and Gulf Coast south along both lowlands of Mexico and through Middle America and South America (also Tobago and Trinidad) west of Andes to Ecuador and east of Andes to eastern Peru, Bolivia, northern Argentina, and Uruguay (AOU 1983). NON-BREEDING: southeastern U.S. from central South Carolina, southern Georgia, Florida, and Gulf Coast southward; essentially resident in breeding range in Cuba, Isle of Pines, Middle America, and South America. Casual northward after breeding season (AOU 1983).
Anhingas have an average body length of 85 cm, weight of 1350 g, wingspan of 117 cm, and bill length of 81 mm. The head is small and appears to be merely an extension of its long snake-like neck. In the neck, the 8th and 9th cervical vertebrae create a hinge-like apparatus that allows the quick catching of prey. The long, sharp, serrated bill also aids it in hunting. The wings are broad, allowing it to soar, and the feet are webbed to facilitate swimming. The physical structure of the legs is, however, more suited to crawling out of water onto land and for climbing bushes and trees. The tail is long and is used for providing lift, steering, braking, and balancing. When spread in flight, the tail resembles that of a turkey. The overall body shape of anhingas resembles that of a cormorant; the hunting action of the head and neck is more similar to a heron.
Anhingas are sexually dimorphic; males have brighter colors than females. Males have greenish-black plumage overall, accentuated by silver-gray feathers on the upper back and wings that are edged with long white plumes. They also have black crests. Females are brown with a lighter brown head and neck; juveniles are a uniform brown color. Molting of all flight feathers at the same time render them flightless for a while. Unlike some aquatic birds, all of the body feathers become completely wet upon contact with the water, allowing them to dive through the water more easily. This feature, however, causes them to have little buoyancy, to lose heat quickly, and hinders flight.
Average mass: 1350 g.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently
Average mass: 1080 g.
Average basal metabolic rate: 3.2258 W.
- Hennemann, W. 1982. Energetics and spread-winged behavior of anhingas in Florida. Condor, 84(1): 91-96.
- Scott, S. 1983. Field Guide to the Birds of North America. Washington D.C.: National Geographic Society.
Length: 89 cm
Weight: 1235 grams
Habitat and Ecology
Anhinga anhinga prefers freshwater and coastal aquatic habitats that include shrub or tree-covered islands or shores; these habitats include lakes, marshes, swamps, mangrove swamps, shallow coastal bays, and lagoons. Within such habitats, anhingas are able to stalk slow-moving prey and seek refuge from danger in the water, and perch and sun itself in the treetops.
Aquatic Biomes: lakes and ponds; rivers and streams; coastal
Other Habitat Features: riparian ; estuarine
- Owre, O. 1967. Adaptations for locomotion and feeding in the Anhinga and the Double-crested Cormorant. Ornithological Monographs, 6: 138-276.
Comments: Freshwater swamps, lakes, and sluggish streams at low elevations and, in tropical regions, primarily around brackish lagoons and in mangroves (AOU 1983). In Louisiana, most nesting areas are freshwater, some brackish; mainly cypress swamps, sometimes in freshwater marshes (Portnoy, cited by Johnsgard 1993). Favored habitats have areas of open nonturbid water (Palmer 1962). Nests near top of tree or shrub 1-6 m above water or ground, often near wading birds and cormorants. Male establishes nest site, both sexes build.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
In the U.S., northerly breeders are migratory, arrive in breeding areas March-April, depart by early October (Palmer 1962). Basically nonmigratory in south.
Anhingas prey primarily on fish (Percidae, Centrarchidae, Peociliidae, Cyprinodontidae), but their diet can also include aquatic invertebrates and insects. Although not particularly fast swimmers, they are effective aquatic hunters, relying on their quick necks and sharp bills to catch prey. They target slower-moving species of fish and stalk them underwater, finally striking out with their long neck and spearing the prey with the beak. They then bring the prey above water and manipulate it in order to swallow the fish head first.
Animal Foods: fish; insects; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Comments: Eats mainly fishes; also other aquatic vertebrates and invertebrates (see Johnsgard 1993 for details). Dives from water surface or while flying or from perch, spears fishes on bill (Palmer 1962).
Generally alone or in pairs.
Life History and Behavior
Communication and Perception
Normally quiet birds, vocalizations include clicks, rattles, croaks, and grunts. Anhingas typically call while on or near the nest, and occasionally while flying or perching. They are particularly silent and elusive when flightless due to molting.
Communication Channels: acoustic
Status: wild: 16.4 (high) years.
Status: wild: 143 months.
Lifespan, longevity, and ageing
Anhingas are monogamous and pairs may reuse nests from year to year. The male begins courtship by soaring and gliding, followed by marking a possible nest location with leafy twigs. Then he performs behavioral displays to attract the female. Once the pair is formed, the male gathers nesting material, while the female builds a platform nest, which is usually on a branch overhanging water or in open areas in the tops of trees. The female constructs the nest by weaving sticks together and padding it with live twigs and green leaves. Usually, the highly territorial males defend any threats to nesting territories with extensive displays and even fighting. If another male approaches the territory, the resident male spreads its wings and snaps its beak. If no retreat occurs, fighting will commence by pecking at each other's heads and necks. Females are less aggressive, but will defend the nest if necessary.
Mating System: monogamous
Anhingas are believed to reach sexual maturity around two years of age. Breeding occurs seasonally in North America. In sub-tropical or tropical latitudes, breeding can occur throughout the year, or be triggered by wet or dry seasons. The female lays one egg every one to three days, until she has a clutch anywhere from two to six eggs. Average clutch size is four eggs. The oval-shaped eggs are bluish-white or pale green, sometimes occurring with brown speckles.
Breeding season: Anhingas may breed seasonally or throughout the year, depending on latitude.
Average eggs per season: 4.
Range time to hatching: 25 to 30 days.
Average fledging age: 6 weeks.
Key Reproductive Features: seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
The parents share in incubating the eggs for 25 to 30 days. In Mexico, anhingas were documented as performing particular displays when males and females switch incubating duties at the nest. These displays included two parents vocalizing to one another, and the incubating bird neck-stretching toward the mate. After the birds intertwined necks and the returning bird passed nesting material to the incubating bird, the two switched places. Upon hatching, anhinga chicks are naked and helpless. They eventually grow a white down on their belly side and a dark down on their back side. At first the parents feed the chicks by dripping fluid and regurgitated material from partially digested fish down their throats. As the chicks grow older, they shove their heads down the parents' beaks to get this food material. The chicks are in the nest approximately three weeks, but if threatened, are able to drop into the water and swim away, later climbing out of the water and back into the nest. At the end of three weeks, they are able to climb out of the nest to a branch, and fledge at approximately six weeks. They stay with their parents for several more weeks before becoming independent.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Protecting: Male, Female)
- Burger, J., L. Miller, D. Hahn. 1978. Behavior and Sex Roles of Nesting Anhingas at San Blas, Mexico. Wilson Bull., 90(3): 359-375.
- del Hoyo, J., A. Elliot, J. Sargatal. 1992. Handbook of the Birds of the World. Vol. 1, Ostrich to Ducks.. Barcelona: Lynx Edicions.
Eggs are laid from February through June (peak from mid-March through April) in Florida, April-early June in Texas-Louisiana (limited data), July on the west coast of Mexico (see Johnsgard 1993). Clutch size usually is 2-5 (mean between 3 and 4 in the U.S.). Incubation, by both sexes in turn, lasts about 25-28 days. Young are tended by both parents, can fly by 6 weeks, independent at 8 weeks. Sexually mature probably in 2 years. Nests singly or in small colonies, up to 100s of pairs, separated into clusters of 8-12 pairs.
Molecular Biology and Genetics
Barcode data: Anhinga anhinga
There are 5 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Anhinga anhinga
Public Records: 5
Specimens with Barcodes: 7
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
- 2008Least Concern
- 2004Least Concern
In the Americas, anhingas are abundant, although their aquatic habitats are threatened. DDT was found to have an effect on the reproductive success of these birds and banning of this pesticide in North America has benefited those birds that breed in the southern United States.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
National NatureServe Conservation Status
Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Comments: DDE-associated eggshell thinning and reduced hatching success has been observed in Mississippi (see Johnsgard 1993).
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
In North America, anhingas have no particular economic impact, particularly since they do not eat the fish that humans might.
Economic Importance for Humans: Positive
Anhingas and their eggs are eaten by humans in parts of Asia.
Positive Impacts: food
The Anhinga (Anhinga anhinga), sometimes called Snakebird, Darter, American Darter, or Water Turkey, is a water bird of the warmer parts of the Americas. The word anhinga comes from the Brazilian Tupi language and means devil bird or snake bird.
It is a cormorant-like bird with an average body length of 85 cm (33 in), a wingspan of 117 cm (46 in), and a mass of up to 1.35 kg (3.0 lb). It is a dark-plumaged piscivore with a very long neck, and often swims with only the neck above water. When swimming in this style the name Snakebird is apparent, since only the colored neck appears above water the bird looks like a snake ready to strike. They do not have external nares (nostrils) and breathe solely through their epiglottis.
The Anhinga is placed in the darter family, Anhingidae, and is closely related to Indian (Anhinga melanogaster), African (A. rufa), and Australian (A. novaehollandiae) Darters. Like other darters, the Anhinga hunts by spearing fishes and other small prey using its sharp, slender beak.
Distribution and migration[edit source | edit]
Anhinga species are found all over the world in warm shallow waters. The American Anhinga has been subdivided into two subspecies, A. a. anhinga and A. a. leucogaster, based on their location. A. a. anhinga can be found mainly east of the Andes in South America and also the islands of Trinidad and Tobago. A. a. leucogaster can be found in the southern United States, Mexico, Cuba, and Grenada.
Only birds that do not live in the extreme north and south of their range migrate and do so based on temperature and available sunlight. Anhingas will migrate towards the equator during winter but this range is "determined by the amount of sunshine to warm the chilled birds". Although not in their usual range, anhingas have been found as far north as the states of Pennsylvania and Wisconsin in the United States.
Kettles of anhingas often migrate with other birds and have been described as resembling black paper gliders.
Physical description and taxonomy[edit source | edit]
The A. anhinga species is a large bird and measures approximately 89 cm (35 in) in length, with a range of 75–95 cm (30–37 in), with a 1.14 m (3.7 ft) wingspan. The A. a. anhinga subspecies is larger than A. a. leucogaster and has "broader buffy tail lips". They weigh on average around 1.22 kg (2.7 lb), with a range of 1.04–1.35 kg (2.3–3.0 lb). The bill is relatively long (about twice the length of the head), sharply pointed and yellow as are the webbed feet.
Most of the male Anhinga's body is a glossy black green with the wings, base of wings, and tail being a glossy black blue. The tip of the tail has white feathers. The back of the head and the neck have elongated feathers that have been described as gray or light purple white. The upper back of the body and wings is spotted or streaked with white.
The female Anhinga is similar to the male Anhinga except that it has a pale gray-buff or light brown head, neck, and upper chest. The lower chest or breast is a chestnut color and as compared to the male, the female has a more brown back.
The hatchling starts out bald but gains tan down within a few days of hatching. Within two weeks the tan down has been replaced by white down. Three weeks after hatching, the first juvenile feathers appear. Juveniles are mostly brown until first breeding after the second or third winter.
This bird is often mistaken for the Double-crested Cormorant due to its similar size and behavior. However, the two species can be differentiated by their tails and bills. The tail of the anhinga is wider and much longer than that of the cormorant. The bill of the anhinga is pointed, while the bill of the cormorant has a hook-tip.
Behaviour[edit source | edit]
Unlike ducks, the Anhinga is not able to waterproof its feathers using oil produced by the uropygial gland. Consequently, feathers can become waterlogged, making the bird barely buoyant. However, this allows it to dive easily and search for underwater prey, such as fish and amphibians. It can stay down for significant periods.
When necessary, the Anhinga will dry out its wings and feathers, with the resemblance of the semicircular full-spread shape of its group of tail feathers while drying them out, to that of true meleagrine males lending the name "water turkey" to it. It will perch for long periods with its wings spread to allow the drying process, as do cormorants. If it attempts to fly while its wings are wet, it has great difficulty getting off the water and takes off by flapping vigorously while "running" on the water.
Anhinga will often search for food in small groups.
Conservation status[edit source | edit]
The Anhinga is protected in the US under the Migratory Bird Treaty Act of 1918. The number of individual anhingas has not been estimated but they are considered to be of least concern because of the frequency of their occurrence in their 15,000,000 km2 (5,800,000 sq mi) global range.
References[edit source | edit]
- BirdLife International (2012). "Anhinga anhinga". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 16 July 2012.
- Nellis, David W. (2001). Common Coastal Birds of Florida and the Caribbean. Pineapple Press, Inc. p. 110. ISBN 978-1-56164-191-8.
- Blake, Emmet Reid (1953). Birds of Mexico: a guide for field identification. University of Chicago Press. pp. 151–152. ISBN 0-226-05641-4.
- Gerald M. McWilliams, Daniel W. Brauning (1999). Birds of Pennsylvania. Cornell University Press. p. 43. ISBN 978-0-8014-3643-7.
- Robbins,Samuel D. (1991). Wisconsin Birdlife: Population and Distribution Past and Present. University of Wisconsin Press. pp. 127–128. ISBN 978-0-299-10260-9.
- Ted L. Eubanks, Robert A. Behrstock, Ron J. Weeks (2006). Birdlife of Houston, Galveston, and the Upper Texas Coast. Texas A&M University Press. p. 70. ISBN 978-1-58544-510-3.
- Sibley, David Allen (2003). The Sibley Field Guide to Birds of Eastern North America. Alfred A. Knopf, New York. p. 45. ISBN 0-679-45120-X.
- David S. Maehr, H. W. Kale, Herbert W. Kale, II (2005). Florida's Birds: A Field Guide and Reference. Pineapple Press Inc. pp. 33, 38. ISBN 1-56164-335-1.
- Audubon, John James (1843). The Birds of America. J.B. Chevalier. pp. 443–457.
- Tom Wood, Sheri L. Williamson, Jeffrey Glassberg (2005). Birds of North America. Sterling Publishing Company, Inc. p. 50. ISBN 1-4027-2821-2.
- Chapman, Frank M. Handbook of Birds of Eastern North America. Harvard University. p. 93.
- Burton, Maurice; Burton Robert (2002). International Wildlife Encyclopedia. Marshall Cavendish. p. 646. ISBN 0-7614-7271-1.
- Gregware, Bill; Gregware, Carol (1997). Guide to the Lake Okeechobee Area. Pineapple Press Inc. p. 54. ISBN 1-56164-129-4.
- Jon Fjeldså, Niels Krabbe, Povl Jørgensen, Jens Ole Byskov (1990). Birds of the High Andes. Apollo Books. p. 74. ISBN 87-88757-16-1.
- Peterson, Roger Tory (1998). A Field Guide to the Birds of Texas. Houghton Mifflin Harcourt. p. 130. ISBN 0-395-92138-4.
- U.S. Fish and Wildlife Service (1995). "Birds Protected by the Migratory Bird Treaty Act". Archived from the original on 2008-05-08. Retrieved 2008-09-15
Names and Taxonomy
Comments: Relationships to A. rufa of Africa, A. melanogaster of Southeast Asia, and A. novaehollandiae of Australian region remain in doubt (AOU 1983, 1998).